Belgium prosecutors have charged a fourth individual with terrorism offences, according to reports.
BREAKING: Belgian authorities charge a fourth suspect with terrorism offenses.
Reuters also reported prosecutors had charged the man, who was held in custody, with participating in the Paris terror attacks.
Another 15 people who had been arrested in an operation on Sunday night have now been released, according to a statement from prosecutors.
Two of five people detained earlier on Monday were also released, it said.
Andy Murray says Great Britain's tennis players feel "very comfortable" in Belgium as they prepare to play in Friday's Davis Cup final
Walking round Brussels today is a bit like walking round a city on Christmas Day - it's a touch surreal.
Former British number one Tim Henman has cancelled his plans to attend the Davis Cup final with his family amid security fears in Belgium.